Exogenous fetuin-A protects against sepsis-induced myocardial injury by inhibiting oxidative stress and inflammation in mice

JNK inhibition mitigates sepsis-associated encephalopathy via attenuation of neuroinflammation, oxidative stress and apoptosis

Sepsis-associated encephalopathy (SAE) is a severe complication of sepsis, leading to cognitive dysfunction and neuronal damage. C-Jun N-terminal kinases (JNKs), a subset of the MAP kinase family, have attracted substantial interest for their role in cellular events during sepsis conditions. Previous investigations have established the involvement of JNK signaling against memory impairment and abnormal synaptic plasticity. However, the present study is the first to investigate the effects of JNK inhibition in sepsis-associated cerebral injury and cognitive impairments. This study investigated the neuroprotective effects of SP600125, a selective JNK inhibitor, in cecal ligation and puncture (CLP) mouse model of sepsis. CLP-induced sepsis resulted in significant cognitive impairments, as assessed by the open field test, inhibitory avoidance test, morris water maze, and novel object recognition test. Additionally, septic mice exhibited increased serum levels of neuronal injury markers (S100B and NSE), pro-inflammatory cytokines (TNF-α and IL-1β), and oxidative stress markers (MDA), along with decreased antioxidant levels (GSH, SOD, and CAT). Histological analysis revealed neuronal pyknosis, degeneration, and loss of Nissl bodies in the cortex and hippocampus of septic mice. Furthermore, sepsis-induced blood-brain barrier dysfunction was evident from increased cerebral edema. Treatment with SP600125 (10, 30, and 50 mg/kg) significantly attenuated CLP-induced cognitive deficits, neuronal injury, neuroinflammation, oxidative stress, and apoptosis in a dose-dependent manner. The present study provides preliminary evidence that JNK inhibition by SP600125 exerts neuroprotective effects against sepsis-induced encephalopathy in vivo via suppression of neuroinflammation, oxidative stress, and apoptosis.

Histopathological effects of hypervitaminosis-D and the protective role of fetuin-A in renal, hepatic, and cardiac tissues in a murine model

Hypervitaminosis D leads to toxic effects, including hypercalcemia, which can cause severe damage to various organs. Fetuin-A, a glycoprotein with anti-inflammatory properties, may protect tissues from such damage. This study explores the role of Fetuin-A in mitigating hypervitaminosis D-induced damage in renal, hepatic, and cardiac tissues. The objectives of this study were to: (1) Assess the extent of tissue damage from high-dose vitamin D in a murine model by examining the histopathological changes in liver, kidney and heart. (2) Investigate Fetuin-A's protective effect against this damage. Thirty-six albino rats were divided into four groups: (1) control, (2) vitamin D toxicity, (3) Fetuin-A + vitamin D, and (4) Fetuin-A only. Vitamin D was administered subcutaneously at 250 μg/20 g/day for 3 days. Fetuin-A was given at 100 μl/20 g, starting 7 days before vitamin D treatment. Histopathological analysis of liver, kidney, and heart tissues was performed using H&E and Alizarin Red staining and findings were analysed statistically. Vitamin D toxicity caused significant tissue damage, including apoptosis, inflammation, and calcification in the liver, kidneys, and heart. Pre-treatment with Fetuin-A reduced calcification and inflammation, preserving tissue architecture. Fetuin-A-only rats showed no damage or calcification. Fetuin-A provided statistically significant protection against vitamin D-induced damage, reducing oxidative stress and calcification in affected organs. These findings suggest Fetuin-A could be a potential therapeutic agent for hypervitaminosis D.

A focus on c-Jun-N-terminal kinase signaling in sepsis-associated multiple organ dysfunction: Mechanisms and therapeutic strategies

Sepsis is a life-threatening condition characterized by a widespread inflammatory response to infection, inevitably leading to multiple organ dysfunctions. Extensive research, both in vivo and in vitro, has revealed key factors contributing to sepsis, such as apoptosis, inflammation, cytokine release, oxidative stress, and systemic stress. The changes observed during sepsis-induced conditions are mainly attributed to altered signal transduction pathways, which play a critical role in cell proliferation, migration, and apoptosis. C-Jun N-terminal kinases, JNKs, and serine/threonine protein kinases in the mitogen-activated super family have gained considerable interest for their contribution to cellular events under sepsis conditions. JNK1 and JNK2 are present in various tissues like the lungs, liver, and intestine, while JNK3 is found in neurons. The JNK pathway plays a crucial role in the signal transduction of cytokines related to sepsis development, notably TNF-α and IL-1β. Activated JNK leads to apoptosis, causing tissue damage and organ dysfunction. Further, JNK activation is significant in several inflammatory conditions. Pharmacologically inhibiting JNK has been shown to prevent sepsis-associated damage across multiple organs, including the lungs, liver, intestines, heart, and kidneys. Multiple signaling pathways have been implicated in sepsis, including JNK/c-Myc, Mst1-JNK, MKK4-JNK, JNK-dependent autophagy, and Sirt1/FoxO3a. The review examines the role of JNK signaling in the development of sepsis-induced multiple-organ dysfunction through specific mechanisms. It also discusses different therapeutic approaches to target JNK. This review emphasizes the potential of JNKs as targets for the development of therapeutic agents for sepsis and the associated specific organ damage.

Knockdown of OLFM4 protects cardiomyocytes from sepsis by inhibiting apoptosis and inflammatory responses

Sepsis is a systemic inflammatory response that can result in cardiac insufficiency or heart failure known as septic myocardial injury. A previous study identified OLFM4 as an important gene in sepsis through bioinformatics analysis. However, there is limited research on the regulatory functions of OLFM4 in sepsis-triggered myocardial injury, and the related molecular mechanisms remain unclear. In this study, the protein expression of OLFM4 was found to be significantly elevated in LPS-stimulated H9C2 cells, and its suppression enhanced cell proliferation and reduced cell apoptosis in LPS-triggered H9C2 cells. The inflammatory factors TNF-α, IL-6, and IL-1β were increased after LPS treatment, and these effects were mitigated after silencing OLFM4. Moreover, it was confirmed that inhibition of OLFM4 attenuated the NF-κB signaling pathway. In conclusion, the knockdown of OLFM4 protected cardiomyocytes from sepsis by inhibiting apoptosis and inflammatory responses via the NF-κB pathway. These findings provide important insights into the regulatory functions of OLFM4 in the progression of septic myocardial injury.

Polydopamine modification of polydimethylsiloxane for multifunctional biomaterials: Immobilization and stability of albumin and fetuin-A on modified surfaces

The surface of polydimethylsiloxane (PDMS) can be modified to immobilize proteins; however, most existing approaches are limited to complex reactions and achieving multifunctional modifications is challenging. This work applies a simple technique to modify PDMS using polydopamine (PDA) and investigates immobilization of multiple proteins. The surfaces were characterized in detail and stability was assessed, demonstrating that in a buffer solution, PDA modification was maintained without an effect on surface properties. Bovine serum albumin (BSA) and bovine fetuin-A (Fet-A) were used as model biomolecules for simultaneous or sequential immobilization and to understand their use for surface backfilling and functionalization. Based on 125I radiolabeling, amounts of BSA and Fet-A on PDA were determined to be close to double that were obtained on control PDMS surfaces. Following elution with sodium dodecyl sulfate, around 67% of BSA and 63% of Fet-A were retained on the surface. The amount of immobilized protein was influenced by the process (simultaneous or sequential) and surface affinity of the proteins. With simultaneous modification, a balanced level of both proteins could be achieved, whereas with the sequential process, the initially immobilized protein was more strongly attached. After incubation with plasma and fetal bovine serum, the PDA-modified surfaces maintained over 90% of the proteins immobilized. This demonstrates that the biological environments also play an important role in the binding and stability of conjugated proteins. This combination of PDA and surface immobilization methods provides fundamental knowledge for tailoring multifunctional PDMS-based biomaterials with applications in cell-material interactions, biosensing, and medical devices.